953
FNCA52 TJSJ 201930
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST WED MAY 20 2026
DISCUSSION
INCREASED MOISTURE COULD PREVENT RH VALUES FROM DECREASING BELOW
THRESHOLD VALUES FOR PROLONGED PERIODS; HOWEVER, RAINFALL SHOULD
AGAIN REMAIN LIMITED ACROSS THE SOUTHERN PLAINS, ALLOWING
RELATIVE HUMIDITY TO DROP TO CRITICAL FIRE WEATHER THRESHOLDS IN
THE REGION. ADDITIONALLY, SUSTAINED WINDS OF 15 TO AROUND 20 MPH,
WITH HIGHER GUSTS, COMBINED WITH ELEVATED KBDI VALUES, WILL FAVOR
THE RAPID SPREAD OF WILDFIRES ACROSS THE SOUTHERN COASTAL PLAINS.
THE LOW 7-DAY PERCENT OF NORMAL RAINFALL WILL ALSO PERSIST ACROSS
THE SOUTHEASTERN COASTAL PLAINS. FIRE MANAGEMENT PARTNERS ARE
ONCE AGAIN URGED TO REMAIN VIGILANT.
PRZ014-210800-
SOUTHEAST COASTAL PLAINS-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 10 40
TEMP (24H TREND) 72 (-2) 90 (+3) 72 90
RH % (24H TREND) 86 (+2) 49 (-5) 92 51
WIND 20FT/EARLY(MPH) E 13 E 16 G23 E 12 E 13
WIND 20FT/LATE(MPH) E 11 E 16 G23 E 11 E 14 G22
MIXING HGT(FT-AGL/MSL) 5550 4710
TRANSPORT WND (MPH) E 18 E 15
VENT RATE (KT-FT) 88800 61230
DISPERSION 5 5
DSI 5 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ015-210800-
SOUTHERN HILLS-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 30 10 50
TEMP (24H TREND) 68 (-3) 87 (+4) 68 86
RH % (24H TREND) 93 (+2) 56 (-10) 96 60
WIND 20FT/EARLY(MPH) E 13 E 13 E 13 E 12
WIND 20FT/LATE(MPH) E 13 SE 14 E 13 E 12
MIXING HGT(FT-AGL/MSL) 6340 5450
TRANSPORT WND (MPH) E 16 E 14
VENT RATE (KT-FT) 88760 65400
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ016-210800-
NORTH COASTAL PLAINS-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 30 40 10 50
TEMP (24H TREND) 71 (-2) 90 (+2) 71 89
RH % (24H TREND) 94 (+2) 55 (-7) 96 58
WIND 20FT/EARLY(MPH) E 16 E 14 E 16 E 14
WIND 20FT/LATE(MPH) E 13 E 21 E 11 E 17
MIXING HGT(FT-AGL/MSL) 5820 4990
TRANSPORT WND (MPH) E 17 E 15
VENT RATE (KT-FT) 87300 64870
DISPERSION 5 5
DSI 6 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ017-210800-
NORTHERN HILLS-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 10 60 0 70
TEMP (24H TREND) 69 (-2) 88 (+1) 69 88
RH % (24H TREND) 94 (+1) 55 (-7) 96 60
WIND 20FT/EARLY(MPH) E 13 E 13 E 12 E 12
WIND 20FT/LATE(MPH) E 11 E 19 E 9 E 14
MIXING HGT(FT-AGL/MSL) 7250 6170
TRANSPORT WND (MPH) E 14 E 10
VENT RATE (KT-FT) 87000 55530
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ018-210800-
WEST COAST-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS SHOWERS TSTMS
CHANCE PRECIP (%) 10 40 10 60
TEMP (24H TREND) 72 (-1) 91 (+2) 72 91
RH % (24H TREND) 91 (+2) 55 (-8) 93 58
WIND 20FT/EARLY(MPH) E 16 E 14 E 13 E 13
WIND 20FT/LATE(MPH) E 12 E 14 E 10 E 13
MIXING HGT(FT-AGL/MSL) 5160 4530
TRANSPORT WND (MPH) E 13 E 10
VENT RATE (KT-FT) 56760 40770
DISPERSION 5 5
DSI 5 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ019-210800-
EASTERN INTERIOR-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 40 50
TEMP (24H TREND) 69 (-3) 87 (+3) 69 87
RH % (24H TREND) 94 (0) 57 (-8) 97 61
WIND 20FT/EARLY(MPH) E 16 E 14 E 14 E 14
WIND 20FT/LATE(MPH) E 16 E 14 E 13 E 13
MIXING HGT(FT-AGL/MSL) 6640 5310
TRANSPORT WND (MPH) SE 17 E 15
VENT RATE (KT-FT) 99600 69030
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ022-210800-
LUQUILLO MOUNTAIN RANGE-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 50 60 50
TEMP (24H TREND) 68 (-2) 82 (+3) 68 82
RH % (24H TREND) 97 (0) 64 (-9) 99 66
WIND 20FT/EARLY(MPH) E 12 E 12 E 11 E 12
WIND 20FT/LATE(MPH) E 12 E 13 E 11 E 12
MIXING HGT(FT-AGL/MSL) 4630 3900
TRANSPORT WND (MPH) SE 20 E 17
VENT RATE (KT-FT) 78710 58500
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ023-210800-
CENTRAL MOUNTAIN RANGE-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS TSTMS NONE TSTMS
CHANCE PRECIP (%) 0 50 0 60
TEMP (24H TREND) 66 (-3) 86 (+5) 66 86
RH % (24H TREND) 95 (+2) 57 (-11) 96 61
WIND 20FT/EARLY(MPH) E 9 E 10 E 8 E 9
WIND 20FT/LATE(MPH) E 9 SE 11 E 8 E 9
MIXING HGT(FT-AGL/MSL) 7900 6920
TRANSPORT WND (MPH) E 10 E 9
VENT RATE (KT-FT) 71100 55360
DISPERSION 5 5
DSI 2 6 2 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ024-210800-
CAYEY MOUNTAIN RANGE-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 50 60 50
TEMP (24H TREND) 68 (-2) 82 (+2) 68 82
RH % (24H TREND) 96 (-2) 65 (-7) 100 67
WIND 20FT/EARLY(MPH) E 12 E 12 E 11 E 11
WIND 20FT/LATE(MPH) E 11 E 12 E 11 E 11
MIXING HGT(FT-AGL/MSL) 5560 4440
TRANSPORT WND (MPH) E 18 E 16
VENT RATE (KT-FT) 88960 62160
DISPERSION 5 5
DSI 5 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ025-210800-
VIEQUES-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 30 50 50
TEMP (24H TREND) 74 (-2) 87 (+1) 74 87
RH % (24H TREND) 87 (-1) 60 (-3) 90 61
WIND 20FT/EARLY(MPH) E 18 E 17 E 18 E 17
WIND 20FT/LATE(MPH) E 18 E 17 E 17 E 14
MIXING HGT(FT-AGL/MSL) 3790 3410
TRANSPORT WND (MPH) E 20 E 22
VENT RATE (KT-FT) 64430 64790
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ026-210800-
CULEBRA-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 50 40 40
TEMP (24H TREND) 75 (-3) 89 (+2) 76 89
RH % (24H TREND) 86 (0) 58 (-5) 89 59
WIND 20FT/EARLY(MPH) E 18 E 17 E 18 E 17
WIND 20FT/LATE(MPH) E 18 E 18 E 17 E 14
MIXING HGT(FT-AGL/MSL) 3780 3440
TRANSPORT WND (MPH) E 21 E 22
VENT RATE (KT-FT) 68040 65360
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ027-210800-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 30 10 40
TEMP (24H TREND) 73 (-2) 91 (+2) 73 91
RH % (24H TREND) 83 (+2) 49 (-6) 88 51
WIND 20FT/EARLY(MPH) E 18 G26 E 17 G26 E 16 E 17 G25
WIND 20FT/LATE(MPH) E 16 SE 18 G27 E 14 SE 17 G25
MIXING HGT(FT-AGL/MSL) 5240 4740
TRANSPORT WND (MPH) E 21 E 18
VENT RATE (KT-FT) 94320 75840
DISPERSION 5 5
DSI 6 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ001-210800-
SAINT THOMAS AND SAINT JOHN-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER PCLDY PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 20 30
TEMP (24H TREND) 75 (-2) 86 (+1) 75 86
RH % (24H TREND) 89 (+2) 60 (-4) 91 61
WIND 20FT/EARLY(MPH) E 18 E 18 E 18 E 17
WIND 20FT/LATE(MPH) E 19 E 18 E 18 E 14
MIXING HGT(FT-AGL/MSL) 3630 3480
TRANSPORT WND (MPH) E 21 E 22
VENT RATE (KT-FT) 65340 66120
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ002-210800-
ST CROIX-
330 PM AST WED MAY 20 2026
TONIGHT THU THU NIGHT FRI
CLOUD COVER MCLEAR PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 30 30 20
TEMP (24H TREND) 74 (-2) 87 (+1) 75 87
RH % (24H TREND) 85 (-3) 62 (-2) 89 62
WIND 20FT/EARLY(MPH) E 17 E 17 E 18 E 17
WIND 20FT/LATE(MPH) E 17 E 17 E 18 E 14
MIXING HGT(FT-AGL/MSL) 4970 4810
TRANSPORT WND (MPH) E 22 E 20
VENT RATE (KT-FT) 94430 81770
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
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